What is the rate of rise?
As the temperature rises from minute to minute, hour to hour, as shown on the pyrometer, the change can be charted and the increase over time can be calculated. For a bisque the recommended rate is 60°C per hour. For a glaze firing 100°C is a good average. During the firing even if a faulty pyrometer is not giving an accurate reading of the actual temperature in the kiln, it still indicates a change of temperature and is very useful for that purpose. There are critical points in the development of the ceramic body and glaze and as long as these are given attention, in between the rate of rise can be much higher, 150°C, 200°C, 300°C per hour. Particular when the kiln accidentally turns off at some point during a firing it doesn’t hurt to do a fast catch-up within limits. With awareness of the critical points (see following) it is possible, with increased attention, to do a relatively fast firing, but perhaps it is still best to work safely and carefully. Moreover a slow firing produces
